The precise measurement of magnetic fields (magnetometry) has a variety of scientific applications including NMR detection and gravitational wave detection. More generally, it is an enabling technology for mining exploration, to detect gas, oil and mineral reserves, in airports for automated detection of plane movements with less building induced interference than radar, and in medicine for the detection of magnetic fields produced by the heart (magento-cardiography or “MCG”) or the brain (magento-encephalography or “MEG”).
State of the art sensors with sensitivities around 1 fT/√Hz are the widely used SQUID magnetometers, operated at cryogenic temperatures typically below 10K. The more recently developed spin-exchange relaxation-free (SERF) atomic magnetometers are potentially more sensitive and do not require cryogenic refrigeration but are orders of magnitude larger in size (˜1 cm3) and must be operated in a near-zero magnetic field.
It would be desirable to provide a magnetometer which overcomes or at least ameliorates the drawbacks of existing magnetic field sensors.
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